16,000 feet. A bit later, just before we went to 32,000 , we saw the crater of a volcano, the part of the tour that was cancelled. I would have taken a pic, but there wasn't enough time. I had to seconds to look at it, and then it was covered by the clouds. I saw lotsa smaller craters in it, and huge caldera. It was roughly the size of 5 football fields (the crater).